a. Field of the Invention
The present invention generally pertains to electronic communications and more particularly to electronic parallel data communications.
b. Description of the Background
There are two standard communication models for electronic communications, serial and parallel. Serial communications send all data along a single communications channel. For a digital signal, a serial connection is decoded by setting a clock speed for the signal and sampling the communication at each clock tick. Each sample is set to a 1 or 0 based on whether the sampled signal was high or low. The receiving system then blocks out the data received into frames of a specified number of data bits. Often the number of data bits in a frame is set to 8 bits (or a byte) with possible additional bits for parity and/or stop status indicators.
A parallel communication connection is essentially a group of serial communication channels operating together to provide faster data throughput than is possible with a single serial connection. Parallel communication connections typically consist of a power of two (i.e., 2, 4, 8, 16, and so on) data channels operating synchronously to provide data communications. Eight data channels is a common number of parallel data channels since eight data channels provides data in even byte increments. A parallel communication connection may work similar to a serial connection by sampling all data channels at a specific clock speed and then putting the sampled data together according to the appropriate communication protocol. A parallel communication connection may also include a frame communication channel that permits a receiver to coordinate the data channels if there is any possibility that the data channels may have slightly different transmit times for each individual physical communication channel. A communications channel may be any physical communication channel including a wire, a printed circuit board trace, or a fiber optic link. As communication speeds have increased, the use of a frame channel within a parallel communication connection has become more common. RapidIO, InfiniBand, Advanced Switching Interconnect (ASI), and System Packet Interface (SPI) are examples of modem parallel communication protocols that employ a frame communication channel in addition to multiple parallel data communication channels.
Information on the RapidIO specification is kept by the RapidIO Trade Association, 3925 W. Braker Lane, Suite 325, Austin, Tex. 78759, telephone number 512-305-0070, and web site www.rapidio.org. RapidIO is a registered trademark of the RapidIO Trade Association.
Information on the InfiniBand specification is kept by the InfinBand Trade Association, 5440 SW Westgate Drive, Suite 217, Portland, Oreg. 97221, telephone number 503-291-2565, and web site www.infinibandta.org. InfiniBand is a registered trademark of System I/O, Inc., doing business as InfiniBand Trade Association.
Information on the Advanced Switching Interconnect (ASI) specification is kept by the Advanced Switching Interconnect SIG, c/o VTM, 5440 SW Westgate Drive, Suite 217, Portland, Oreg. 97221, telephone number 503-291-2566, and web site www.infinibandta.org.
Information on the System Packet Interface (SPI) specification is kept by the Optical Internetworking Forum, 39355 California Street, Suite 307, Fremont, Calif. 94538, telephone number 510-608-5928.